This study focuses on the mechanical response of silicon on porous silicon\nbilayer cantilevers ended with a seismic mass. The porous silicon is intended\nto provide an alternative to decrease the cantilever stiffness for low-frequency\nMEMS applications. The first eigenfrequency of the cantilever is obtained\nusing static deflection obtained under classical Euler-Bernoulli assumptions\nand Rayleigh method. In order to estimate the errors due to small-strain approximation\nand Euler-Bernoulli theory, the analytical results were validated\nthrough 3D finite element simulations for different cantilever geometries and\nporosities. Both bulk silicon and silicon on porous silicon bilayer cantilevers\nended with a seismic mass were fabricated and we measured the first eigenfrequency\n(f0) and quality factor (Q) by using a laser Doppler vibrometer. In\nagreement with the theoretical predictions we found that, when compared to\nbulk silicon cantilevers, the first eigenfrequency of a bilayer cantilever containing\n6% porous silicon (at 50% porosity) on 94% bulk silicon is lowered by\n5%,.........
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